1. Field of the Invention
The present invention relates to a composition containing a silicone-based aerosol material and uses of the composition. More particularly, the present invention relates to a silicone-based aerosol lubricating composition and a silicone-based aerosol containing a flammable composition. The present invention also relates to an improved aerosol spray system for dispensing a silicone-based composition.
2. Description of the Related Art
Silicone containing aerosol compositions are well known in uses such as lubricating compositions. See, e.g., U.S. Pat. No. 5,534,173. Most of the known aerosols containing silicones, however, use a solvent to carry the silicone and a propellant to push the silicone and solvent blend out of the aerosol can. While enabling performance, a significant number of these solvents and propellants are known to have adverse effects on the environment and worker safety. Moreover, in recent years there has been an effort to reduce the use of volatile organic compounds and ozone depleting substances in view of their detrimental impact on the environment, their flammability and their hazards in the work place. In addition, in recent years there has also been a trend away from chlorine containing propellants in view of their damaging effects to the ozone layer of the atmosphere and their suspected carcinogenic nature.
The use of silicone-based sprays to lubricate die faces for the manufacture of synthetic fibers in fiber spinning processes is also well known. However, conventional lubricants used to coat the die face suffer from the disadvantage that the worker applying the lubricant is exposed to the heat of the die for a prolonged amount of time needed to adequately lubricate the die face. Therefore, there is a need in the art to provide a silicone-based lubricant which is environmentally friendly, non-flammable, non-carcinogenic and that can also be quickly dispensed from its container under adverse application conditions.
It is generally understood in the art that silicones are heat stable and nonflammable under normal conditions. It is, however, recognized in the art that under certain conditions silicones can become flammable. For example, U.S. Pat. No. 4,155,864 discloses that when silicone fluids are sprayed from leaks in hoses there is a greater than normal fire potential, if ignition sources is also present. In particular, the ""864 patent observes that when silicones are sprayed from hoses they can become flammable. Accordingly, an object of their ""864 patent is to prevent the flammability of silicone fluids by adding a high molecular weight poly(diorganosiloxane) polymer to the composition. The high molecular weight polymer increases the viscosity of these silicone fluids, which normally have a viscosity ranging from about 7 to about 50 centistokes, to a level of viscosity at which the silicones are no longer considered a flammability hazard. The ""864 patent theorizes that the addition of the higher molecular weight polymer alters the formation of silicone particles in such a way as to hinder the formation of separate silicone particles, and thus the atomization of the silicone being sprayed from a hose. The whole gist of the ""864 patent is to avoid flammability; the ""864 patent does not teach how to provide a composition which is reliably flammable use after use.
Aerosol systems in which the propellant is miscible in the active ingredient are also known. See for example, U.S. Pat. No. 5,935,554, which discloses propellants dissolved in active ingredients, specifically for use in perfumes and insecticides. The ""554 patent broadly discloses that propellants can be fluorocarbon, hydrocarbon, hydrofluorocarbon, hydrochlorofluorocarbon, dimethyl ether and any other suitable propellants. The ""554 patent exemplifies the use of propellants HCP58 and P28 both of which are hydrocarbons. It is generally known in the art that fluorocarbons are not useful as solubilizing agents. As a result, solubilizing agents are typically required to ensure the performance of fluorocarbon-based formulations. Aerosol systems that contain fluorocarbon and hydrofluorocarbons are also well known in the art. For example, U.S. Pat. No. 5,476,604 discloses compositions which can include a variety of fluorocarbons and hydrofluorocarbons along with release agents such as waxy esters, paraffin or synthetic waxes, polyethylene wax, metal soaps and silicones. The ""604 patent indicates that solubilizing agents such as flammable gasoline fractions for the release agents are preferred, because, according to the ""604 patent, the fluorocarbons have only a slight dissolving power. In fact, all of the examples of the ""604 patent require at least 25 wt. % of a solubilizing agent. Also, the ""604 patent indicates the composition can contain only up to 40 wt. % of the release agent.
One object of the invention is to provide a silicone-based fluid containing aerosol composition, which overcomes the disadvantages of the known art, described above. Another object of the invention is to provide a silicone-based fluid containing aerosol lubricating composition which is not harmful to the environment and which can be readily sprayed under operating conditions, particularly adverse conditions. Another object of the invention is to provide a flammable silicone-containing aerosol, which can be readily and dependably ignited. Still another object of the invention is to provide a silicone containing aerosol lubricant, which can be rendered inflammable for certain uses.
There has been provided according to one aspect of the present invention an aerosol composition which comprises an admixture of: (a) at least one silicone-based fluid; and (b) at least one fluorine-containing propellant that is soluble in the silicone-based fluid. In a preferred embodiment, the propellant comprises a hydrofluorocarbon, in particular 1,1,1,2-tetrafluoroethane.
According to another aspect of the invention, there has been provided, an aerosol spray system comprising (a) a container; (b) the aerosol composition described above disposed within the container; (c) a metering device; and (d) a spray head.
According to still another aspect of the invention, there has been provided an aerosol lubricating composition comprising the composition described above, wherein the silicone-based fluid is a lubricant. In a preferred embodiment, the composition is a nonflammable, heat stable aerosol lubricating composition which comprises an admixture of: (a) a silicone-based lubricant comprising a silicone functionalized with iron present in an amount of about 45 to 55 wt. %; (b) a second silicone-based lubricant present in an amount of about 15 to 20 wt. % and having a viscosity in the range of about 1,000 to 3,000 centistokes; and (c) 1,1,1,2-tetrafluoroethane present in an amount of about 25 to 35 wt. %, all based on the weight of the entire composition.
Yet another aspect of the invention provides a method of lubricating, comprising: (a) directing a container containing the lubricating composition described above at an article in need of lubrication; and (b) spraying the lubricating composition at the article.
Yet another aspect of the invention provides a flammable aerosol composition comprising an aerosol composition which comprises an admixture of: (a) at least one silicone-based fluid; and (b) at least one fluorine-containing propellant that is soluble in the silicone-based fluid, wherein the silicone-based fluid is a low viscosity silicone-based fluid.
Further objects, features and advantages of the present invention will become apparent from consideration of the preferred embodiments which follows.